1. Field of the Invention
This invention generally relates to a method of and apparatus for stacking articles and, in the embodiment disclosed herein, more particularly to the stacking of articles which may be relatively flimsy and difficult to handle because of a tendency toward dimensional instability.
2. Description of the Prior Art
There are many novel features in this invention, and in my two copending applications Ser. No. 901,670, filed Aug. 29, 1986 and Ser. No. 901,671, filed Aug. 29, 1986, that are applicable to the general art of label formation, label application, and stacking of the labeled articles. However, the overall combination of features in the embodiment disclosed in these three applications is particularly useful in solving the unique problems in handling, adhesive application, label formation and application, restacking, etc. of plastic carriers. These carriers have a top panel with a skirt extending downwardly with surface areas on the skirt for receiving labels. The top panel and skirt have relatively thin walls which, although semi-rigid when retaining a full load of filled containers, are somewhat flimsy and the carriers are dimensionally unstable in comparison with beverage containers, cans, boxes and other fairly rigid packages receiving labels.
In the prior art there are disclosures in U.S. Pat. Nos. 3,954,542; 4,108,706; 4,108,710; and 4,181,555 relating to feeding labels while U.S. Pat. No. 3,779,829 shows label application to opposite sides of an article. U.S. Pat. Nos. 3,915,448; 3,919,040; and 4,323,029 illustrate cam mechanisms for performing various timed machine operations. U.S. Pat. Nos. 3,883,385 and 4,079,875 show label cutters and severing mechanisms. U.S. Pat. No. 4,089,725 illustrates indexing while U.S. Pat. No. 4,124,429 is illustrative of the use of photo elements for control purposes. However none of these patents discloses the combination of mechanisms and functions necessary to solve the unique problems encountered in dealing with articles such as the plastic carriers discussed above. This is not surprising since plastic carriers with surface areas for receiving labels have just recently become available.
With respect to methods and apparatus for stacking, the prior art that appears to be the most relevant is found in U.S. Pat. Nos. 3,037,645; 3,659,695 and 3,895,477. However, neither the unique method and apparatus of the present invention nor the functions performed are found in those disclosures.